1. Field of the Invention
The invention relates to a ventilator for a refrigerator, which automatically adjusts air pressure in a large size refrigerator, a freezer, etc. with the opening and closing of a valve plate for the air pressure adjustment.
2. Prior Art
U.S. Pat. No. 3,952,542 discloses a prior art ventilator for a freezer or the like, which has such a construction that it provides a function of reducing air pressure in the freezer by discharging air therefrom at the time when the freezer pressure is increased and has a function of increasing air pressure in the freezer by introducing air from the outside at the time when the freezer air pressure is reduced.
With such ventilator for a freezer or the like, the two functions of discharging and introducing air are provided by a single ventilator. Therefore, the internal construction of the ventilator is undesirably complicated.